Minimise amount of skipped inspection tests with no upper-bound on GHC version.

[phadej]

We have few tests (in fact just four!) predicated with no-upper bound GHC version, like ghcGE86failure.

% git grep 'ghc.*GE'
optics/tests/Optics/Tests/Core.hs:    ghcGE90failure $(inspectTest $ 'lhs09 === 'rhs09)
optics/tests/Optics/Tests/Core.hs:    ghcGE912failure $(inspectTest $ 'lhs11 === 'rhs11)
optics/tests/Optics/Tests/Core.hs:    ghc810andGE912failure $(inspectTest $ 'lhs16 === 'rhs16)
optics/tests/Optics/Tests/Eta.hs:    ghc82andGE90failure $(inspectTest $ 'eta6lhs === 'eta6rhs)

we should work towards either improving inspection-testing to make these equalities true, or on GHC to make them true (maybe both).

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I have done some not too controversial work on inspection-testing helping with two cases. This is an issue to not forget to push that to the finish line.